Reduce usages of covariant

sqlparser/lib/src/ast/ast.dart

@@ -1,9 +1,9 @@
-import 'package:collection/collection.dart';
 import 'package:meta/meta.dart';
 import 'package:source_span/source_span.dart';
 import 'package:sqlparser/src/analysis/analysis.dart';
 import 'package:sqlparser/src/reader/syntactic_entity.dart';
 import 'package:sqlparser/src/reader/tokenizer/token.dart';
+import 'package:sqlparser/src/utils/ast_equality.dart';
 import 'package:sqlparser/src/utils/meta.dart';
 
 part 'clauses/limit.dart';
@@ -167,7 +167,16 @@ abstract class AstNode with HasMetaMixin implements SyntacticEntity {
   /// Whether the content of this node is equal to the [other] node of the same
   /// type. The "content" refers to anything stored only in this node, children
   /// are ignored.
-  bool contentEquals(covariant AstNode other);
+  @nonVirtual
+  bool contentEquals(AstNode other) {
+    final checker = EqualityEnforcingVisitor(this, considerChildren: false);
+    try {
+      checker.visit(other, null);
+      return true;
+    } on NotEqualException {
+      return false;
+    }
+  }
 
   @override
   String toString() {

sqlparser/lib/src/ast/clauses/limit.dart

@@ -33,7 +33,4 @@ class Limit extends AstNode implements LimitBase {
     // If using a comma, the count is followed by an optional offset
     return [count, if (offset != null) offset];
   }
-
-  @override
-  bool contentEquals(Limit other) => true;
 }

sqlparser/lib/src/ast/clauses/ordering.dart

@@ -26,11 +26,6 @@ class OrderBy extends AstNode implements OrderByBase {
 
   @override
   Iterable<AstNode> get childNodes => terms;
-
-  @override
-  bool contentEquals(OrderBy other) {
-    return true;
-  }
 }
 
 enum OrderingMode { ascending, descending }
@@ -59,9 +54,4 @@ class OrderingTerm extends AstNode implements OrderingTermBase {
 
   @override
   Iterable<AstNode> get childNodes => [expression];
-
-  @override
-  bool contentEquals(OrderingTerm other) {
-    return other.orderingMode == orderingMode && other.nulls == nulls;
-  }
 }

sqlparser/lib/src/ast/clauses/upsert.dart

@@ -29,9 +29,6 @@ class UpsertClause extends AstNode implements HasWhereClause {
       action,
     ];
   }
-
-  @override
-  bool contentEquals(UpsertClause other) => true;
 }
 
 abstract class UpsertAction extends AstNode {}
@@ -47,9 +44,6 @@ class DoNothing extends UpsertAction {
 
   @override
   Iterable<AstNode> get childNodes => const [];
-
-  @override
-  bool contentEquals(DoNothing other) => true;
 }
 
 class DoUpdate extends UpsertAction implements HasWhereClause {
@@ -72,7 +66,4 @@ class DoUpdate extends UpsertAction implements HasWhereClause {
 
   @override
   Iterable<AstNode> get childNodes => [...set, if (where != null) where];
-
-  @override
-  bool contentEquals(DoUpdate other) => true;
 }

sqlparser/lib/src/ast/clauses/with.dart

@@ -22,9 +22,6 @@ class WithClause extends AstNode {
 
   @override
   Iterable<AstNode> get childNodes => ctes;
-
-  @override
-  bool contentEquals(WithClause other) => other.recursive == recursive;
 }
 
 class CommonTableExpression extends AstNode with ResultSet {
@@ -57,11 +54,6 @@ class CommonTableExpression extends AstNode with ResultSet {
   @override
   Iterable<AstNode> get childNodes => [as];
 
-  @override
-  bool contentEquals(CommonTableExpression other) {
-    return other.cteTableName == cteTableName;
-  }
-
   @override
   List<Column> get resolvedColumns {
     final columnsOfSelect = as.resolvedColumns;

sqlparser/lib/src/ast/common/queryables.dart

@@ -55,11 +55,6 @@ class TableReference extends TableOrSubquery
     return visitor.visitTableReference(this, arg);
   }
 
-  @override
-  bool contentEquals(TableReference other) {
-    return other.tableName == tableName && other.as == as;
-  }
-
   @override
   void transformChildren<A>(Transformer<A> transformer, A arg) {}
 
@@ -93,11 +88,6 @@ class SelectStatementAsSource extends TableOrSubquery implements Renamable {
   void transformChildren<A>(Transformer<A> transformer, A arg) {
     statement = transformer.transformChild(statement, this, arg);
   }
-
-  @override
-  bool contentEquals(SelectStatementAsSource other) {
-    return other.as == as;
-  }
 }
 
 /// https://www.sqlite.org/syntax/join-clause.html
@@ -120,11 +110,6 @@ class JoinClause extends Queryable {
 
   @override
   Iterable<AstNode> get childNodes => [primary, ...joins];
-
-  @override
-  bool contentEquals(JoinClause other) {
-    return true; // equality is defined by child nodes
-  }
 }
 
 enum JoinOperator {
@@ -156,27 +141,6 @@ class Join extends AstNode {
     ];
   }
 
-  @override
-  bool contentEquals(Join other) {
-    if (other.natural != natural || other.operator != operator) {
-      return false;
-    }
-
-    if (constraint is OnConstraint) {
-      return other.constraint is OnConstraint;
-    } else if (constraint is UsingConstraint) {
-      final typedConstraint = constraint as UsingConstraint;
-      if (other.constraint is! UsingConstraint) {
-        return false;
-      }
-      final typedOther = other.constraint as UsingConstraint;
-
-      return const ListEquality()
-          .equals(typedConstraint.columnNames, typedOther.columnNames);
-    }
-    return true;
-  }
-
   @override
   R accept<A, R>(AstVisitor<A, R> visitor, A arg) {
     return visitor.visitJoin(this, arg);
@@ -238,9 +202,4 @@ class TableValuedFunction extends Queryable
 
   @override
   bool get visibleToChildren => false;
-
-  @override
-  bool contentEquals(TableValuedFunction other) {
-    return other.name == name;
-  }
 }

sqlparser/lib/src/ast/common/tuple.dart

@@ -28,7 +28,4 @@ class Tuple extends Expression {
 
   @override
   List<Expression> get childNodes => expressions;
-
-  @override
-  bool contentEquals(Tuple other) => true;
 }

sqlparser/lib/src/ast/expressions/aggregate.dart

@@ -62,11 +62,6 @@ class AggregateExpression extends Expression
       if (windowDefinition != null) windowDefinition,
     ];
   }
-
-  @override
-  bool contentEquals(AggregateExpression other) {
-    return other.name == name && other.windowName == windowName;
-  }
 }
 
 /// A window declaration that appears in a `SELECT` statement like
@@ -107,11 +102,6 @@ class WindowDefinition extends AstNode {
   @override
   Iterable<AstNode> get childNodes =>
       [...partitionBy, if (orderBy != null) orderBy, frameSpec];
-
-  @override
-  bool contentEquals(WindowDefinition other) {
-    return other.baseWindowName == baseWindowName;
-  }
 }
 
 class FrameSpec extends AstNode {
@@ -148,14 +138,6 @@ class FrameSpec extends AstNode {
         if (start.isExpressionOffset) start.offset,
         if (end.isExpressionOffset) end.offset,
       ];
-
-  @override
-  bool contentEquals(FrameSpec other) {
-    return other.type == type &&
-        other.excludeMode == excludeMode &&
-        other.start == start &&
-        other.end == end;
-  }
 }
 
 /// Defines how a [FrameBoundary] count rows or groups. See

sqlparser/lib/src/ast/expressions/case.dart

@@ -22,9 +22,6 @@ class CaseExpression extends Expression {
   @override
   Iterable<AstNode> get childNodes =>
       [if (base != null) base, ...whens, if (elseExpr != null) elseExpr];
-
-  @override
-  bool contentEquals(CaseExpression other) => true;
 }
 
 class WhenComponent extends AstNode {
@@ -46,7 +43,4 @@ class WhenComponent extends AstNode {
 
   @override
   Iterable<AstNode> get childNodes => [when, then];
-
-  @override
-  bool contentEquals(WhenComponent other) => true;
 }

sqlparser/lib/src/ast/expressions/cast.dart

@@ -19,9 +19,4 @@ class CastExpression extends Expression {
 
   @override
   Iterable<AstNode> get childNodes => [operand];
-
-  @override
-  bool contentEquals(CastExpression other) {
-    return other.typeName == typeName;
-  }
 }

sqlparser/lib/src/ast/expressions/function.dart

@@ -40,11 +40,6 @@ class FunctionExpression extends Expression
   Iterable<AstNode> get childNodes {
     return [parameters];
   }
-
-  @override
-  bool contentEquals(FunctionExpression other) {
-    return other.name == name;
-  }
 }
 
 /// Marker interface for anything that can be inside the parentheses after a
@@ -67,11 +62,6 @@ class StarFunctionParameter extends FunctionParameters {
 
   @override
   Iterable<AstNode> get childNodes => const Iterable.empty();
-
-  @override
-  bool contentEquals(StarFunctionParameter other) {
-    return true;
-  }
 }
 
 class ExprFunctionParameters extends FunctionParameters {
@@ -92,9 +82,4 @@ class ExprFunctionParameters extends FunctionParameters {
 
   @override
   List<AstNode> get childNodes => parameters;
-
-  @override
-  bool contentEquals(ExprFunctionParameters other) {
-    return other.distinct == distinct;
-  }
 }

sqlparser/lib/src/ast/expressions/literals.dart

@@ -30,9 +30,6 @@ class NullLiteral<T> extends Literal {
   R accept<A, R>(AstVisitor<A, R> visitor, A arg) {
     return visitor.visitNullLiteral(this, arg);
   }
-
-  @override
-  bool contentEquals(NullLiteral other) => true;
 }
 
 class NumericLiteral extends Literal<num> {
@@ -47,9 +44,6 @@ class NumericLiteral extends Literal<num> {
   R accept<A, R>(AstVisitor<A, R> visitor, A arg) {
     return visitor.visitNumericLiteral(this, arg);
   }
-
-  @override
-  bool contentEquals(NumericLiteral other) => other.value == value;
 }
 
 class BooleanLiteral extends Literal<bool> {
@@ -67,11 +61,6 @@ class BooleanLiteral extends Literal<bool> {
   R accept<A, R>(AstVisitor<A, R> visitor, A arg) {
     return visitor.visitBooleanLiteral(this, arg);
   }
-
-  @override
-  bool contentEquals(BooleanLiteral other) {
-    return other.value == value;
-  }
 }
 
 class StringLiteral extends Literal {
@@ -91,11 +80,6 @@ class StringLiteral extends Literal {
   R accept<A, R>(AstVisitor<A, R> visitor, A arg) {
     return visitor.visitStringLiteral(this, arg);
   }
-
-  @override
-  bool contentEquals(StringLiteral other) {
-    return other.isBinary == isBinary && other.value == value;
-  }
 }
 
 enum TimeConstantKind { currentTime, currentDate, currentTimestamp }
@@ -110,11 +94,6 @@ class TimeConstantLiteral extends Literal {
     return visitor.visitTimeConstantLiteral(this, arg);
   }
 
-  @override
-  bool contentEquals(TimeConstantLiteral other) {
-    return other.kind == kind;
-  }
-
   @override
   dynamic get value => throw UnimplementedError('TimeConstantLiteral.value');
 }

sqlparser/lib/src/ast/expressions/reference.dart

@@ -26,11 +26,6 @@ class Reference extends Expression with ReferenceOwner {
   @override
   Iterable<AstNode> get childNodes => const [];
 
-  @override
-  bool contentEquals(Reference other) {
-    return other.tableName == tableName && other.columnName == columnName;
-  }
-
   @override
   String toString() {
     if (tableName != null) {

sqlparser/lib/src/ast/expressions/simple.dart

@@ -18,11 +18,6 @@ class UnaryExpression extends Expression {
 
   @override
   Iterable<AstNode> get childNodes => [inner];
-
-  @override
-  bool contentEquals(UnaryExpression other) {
-    return other.operator.type == operator.type;
-  }
 }
 
 class CollateExpression extends UnaryExpression {
@@ -40,12 +35,6 @@ class CollateExpression extends UnaryExpression {
   R accept<A, R>(AstVisitor<A, R> visitor, A arg) {
     return visitor.visitCollateExpression(this, arg);
   }
-
-  @override
-  bool contentEquals(CollateExpression other) {
-    return super.contentEquals(other) &&
-        other.collateFunction.type == collateFunction.type;
-  }
 }
 
 class BinaryExpression extends Expression {
@@ -68,11 +57,6 @@ class BinaryExpression extends Expression {
 
   @override
   Iterable<AstNode> get childNodes => [left, right];
-
-  @override
-  bool contentEquals(BinaryExpression other) {
-    return other.operator.type == operator.type;
-  }
 }
 
 /// A like, glob, match or regexp expression.
@@ -104,9 +88,6 @@ class StringComparisonExpression extends Expression {
 
   @override
   Iterable<AstNode> get childNodes => [left, right, if (escape != null) escape];
-
-  @override
-  bool contentEquals(StringComparisonExpression other) => other.not == not;
 }
 
 /// `(NOT)? $left IS $right`
@@ -130,11 +111,6 @@ class IsExpression extends Expression {
 
   @override
   Iterable<AstNode> get childNodes => [left, right];
-
-  @override
-  bool contentEquals(IsExpression other) {
-    return other.negated == negated;
-  }
 }
 
 class IsNullExpression extends Expression {
@@ -157,11 +133,6 @@ class IsNullExpression extends Expression {
 
   @override
   Iterable<AstNode> get childNodes => [operand];
-
-  @override
-  bool contentEquals(IsNullExpression other) {
-    return other.negated == negated;
-  }
 }
 
 /// `$check BETWEEN $lower AND $upper`
@@ -187,9 +158,6 @@ class BetweenExpression extends Expression {
 
   @override
   List<Expression> get childNodes => [check, lower, upper];
-
-  @override
-  bool contentEquals(BetweenExpression other) => other.not == not;
 }
 
 /// `$left$ IN $inside`.
@@ -219,9 +187,6 @@ class InExpression extends Expression {
     left = transformer.transformChild(left, this, arg);
     inside = transformer.transformChild(inside, this, arg);
   }
-
-  @override
-  bool contentEquals(InExpression other) => other.not == not;
 }
 
 class Parentheses extends Expression {
@@ -245,7 +210,4 @@ class Parentheses extends Expression {
 
   @override
   Iterable<AstNode> get childNodes => [expression];
-
-  @override
-  bool contentEquals(Parentheses other) => true;
 }

sqlparser/lib/src/ast/expressions/subquery.dart

@@ -19,9 +19,6 @@ class SubQuery extends Expression {
 
   @override
   Iterable<AstNode> get childNodes => [select];
-
-  @override
-  bool contentEquals(SubQuery other) => true;
 }
 
 class ExistsExpression extends Expression {
@@ -41,7 +38,4 @@ class ExistsExpression extends Expression {
 
   @override
   Iterable<AstNode> get childNodes => [select];
-
-  @override
-  bool contentEquals(ExistsExpression other) => true;
 }

sqlparser/lib/src/ast/expressions/variables.dart

@@ -23,11 +23,6 @@ class NumberedVariable extends Expression with Variable {
 
   @override
   Iterable<AstNode> get childNodes => const [];
-
-  @override
-  bool contentEquals(NumberedVariable other) {
-    return other.explicitIndex == explicitIndex;
-  }
 }
 
 class ColonNamedVariable extends Expression with Variable {
@@ -46,9 +41,4 @@ class ColonNamedVariable extends Expression with Variable {
 
   @override
   Iterable<AstNode> get childNodes => [];
-
-  @override
-  bool contentEquals(ColonNamedVariable other) {
-    return other.name == name;
-  }
 }

sqlparser/lib/src/ast/moor/declared_statement.dart

@@ -36,11 +36,6 @@ class DeclaredStatement extends Statement implements PartOfMoorFile {
   @override
   Iterable<AstNode> get childNodes =>
       [statement, if (parameters != null) ...parameters];
-
-  @override
-  bool contentEquals(DeclaredStatement other) {
-    return other.identifier == identifier && other.as == as;
-  }
 }
 
 /// How a statement was declared in a moor file.
@@ -123,11 +118,6 @@ class VariableTypeHint extends StatementParameter {
   void transformChildren<A>(Transformer<A> transformer, A arg) {
     variable = transformer.transformChild(variable, this, arg);
   }
-
-  @override
-  bool contentEquals(VariableTypeHint other) {
-    return other.typeName == typeName;
-  }
 }
 
 /// Set a default value for a dart placeholder.
@@ -150,11 +140,6 @@ class DartPlaceholderDefaultValue extends StatementParameter {
   @override
   Iterable<AstNode> get childNodes => [defaultValue];
 
-  @override
-  bool contentEquals(DartPlaceholderDefaultValue other) {
-    return other.variableName == variableName;
-  }
-
   @override
   void transformChildren<A>(Transformer<A> transformer, A arg) {
     defaultValue = transformer.transformChild(defaultValue, this, arg);

sqlparser/lib/src/ast/moor/import_statement.dart

@@ -18,9 +18,4 @@ class ImportStatement extends Statement implements PartOfMoorFile {
 
   @override
   final Iterable<AstNode> childNodes = const [];
-
-  @override
-  bool contentEquals(ImportStatement other) {
-    return other.importedFile == importedFile;
-  }
 }

sqlparser/lib/src/ast/moor/inline_dart.dart

@@ -31,13 +31,6 @@ abstract class DartPlaceholder extends AstNode {
     return visitor.visitDartPlaceholder(this, arg);
   }
 
-  bool _dartEquals(covariant DartPlaceholder other) => true;
-
-  @override
-  bool contentEquals(DartPlaceholder other) {
-    return other.name == name && other._dartEquals(other);
-  }
-
   T when<T>(
       {T Function(DartExpressionPlaceholder) isExpression,
       T Function(DartLimitPlaceholder) isLimit,

sqlparser/lib/src/ast/moor/moor_file.dart

@@ -28,7 +28,4 @@ class MoorFile extends AstNode {
   /// Returns the imports defined in this file.
   Iterable<ImportStatement> get imports =>
       childNodes.whereType<ImportStatement>();
-
-  @override
-  bool contentEquals(MoorFile other) => true;
 }

sqlparser/lib/src/ast/moor/nested_star_result_column.dart

@@ -17,11 +17,6 @@ class NestedStarResultColumn extends ResultColumn {
   @override
   void transformChildren<A>(Transformer<A> transformer, A arg) {}
 
-  @override
-  bool contentEquals(NestedStarResultColumn other) {
-    return other.tableName == tableName;
-  }
-
   @override
   R accept<A, R>(AstVisitor<A, R> visitor, A arg) {
     return visitor.visitMoorNestedStarResultColumn(this, arg);

sqlparser/lib/src/ast/schema/column_definition.dart

@@ -28,11 +28,6 @@ class ColumnDefinition extends AstNode {
   @override
   Iterable<AstNode> get childNodes => constraints;
 
-  @override
-  bool contentEquals(ColumnDefinition other) {
-    return other.columnName == columnName && other.typeName == typeName;
-  }
-
   /// Finds a constraint of type [T], or null, if none is set.
   T findConstraint<T extends ColumnConstraint>() {
     final typedConstraints = constraints.whereType<T>().iterator;
@@ -87,14 +82,6 @@ abstract class ColumnConstraint extends AstNode {
       throw Exception('Did not expect $runtimeType as a ColumnConstraint');
     }
   }
-
-  @visibleForOverriding
-  bool _equalToConstraint(covariant ColumnConstraint other);
-
-  @override
-  bool contentEquals(ColumnConstraint other) {
-    return other.name == name && _equalToConstraint(other);
-  }
 }
 
 enum ConflictClause { rollback, abort, fail, ignore, replace }
@@ -105,9 +92,6 @@ class NullColumnConstraint extends ColumnConstraint {
 
   NullColumnConstraint(String name, {this.$null}) : super(name);
 
-  @override
-  bool _equalToConstraint(NullColumnConstraint other) => true;
-
   @override
   Iterable<AstNode> get childNodes => const Iterable.empty();
 
@@ -128,9 +112,6 @@ class NotNull extends ColumnConstraint {
 
   @override
   void transformChildren<A>(Transformer<A> transformer, A arg) {}
-
-  @override
-  bool _equalToConstraint(NotNull other) => onConflict == other.onConflict;
 }
 
 class PrimaryKeyColumn extends ColumnConstraint {
@@ -147,13 +128,6 @@ class PrimaryKeyColumn extends ColumnConstraint {
 
   @override
   void transformChildren<A>(Transformer<A> transformer, A arg) {}
-
-  @override
-  bool _equalToConstraint(PrimaryKeyColumn other) {
-    return other.autoIncrement == autoIncrement &&
-        other.mode == mode &&
-        other.onConflict == onConflict;
-  }
 }
 
 class UniqueColumn extends ColumnConstraint {
@@ -166,11 +140,6 @@ class UniqueColumn extends ColumnConstraint {
 
   @override
   void transformChildren<A>(Transformer<A> transformer, A arg) {}
-
-  @override
-  bool _equalToConstraint(UniqueColumn other) {
-    return other.onConflict == onConflict;
-  }
 }
 
 class CheckColumn extends ColumnConstraint {
@@ -185,9 +154,6 @@ class CheckColumn extends ColumnConstraint {
   void transformChildren<A>(Transformer<A> transformer, A arg) {
     expression = transformer.transformChild(expression, this, arg);
   }
-
-  @override
-  bool _equalToConstraint(CheckColumn other) => true;
 }
 
 class Default extends ColumnConstraint {
@@ -202,9 +168,6 @@ class Default extends ColumnConstraint {
   void transformChildren<A>(Transformer<A> transformer, A arg) {
     expression = transformer.transformChild(expression, this, arg);
   }
-
-  @override
-  bool _equalToConstraint(Default other) => true;
 }
 
 class CollateConstraint extends ColumnConstraint {
@@ -217,9 +180,6 @@ class CollateConstraint extends ColumnConstraint {
 
   @override
   void transformChildren<A>(Transformer<A> transformer, A arg) {}
-
-  @override
-  bool _equalToConstraint(CollateConstraint other) => true;
 }
 
 class ForeignKeyColumnConstraint extends ColumnConstraint {
@@ -227,9 +187,6 @@ class ForeignKeyColumnConstraint extends ColumnConstraint {
 
   ForeignKeyColumnConstraint(String name, this.clause) : super(name);
 
-  @override
-  bool _equalToConstraint(ForeignKeyColumnConstraint other) => true;
-
   @override
   Iterable<AstNode> get childNodes => [clause];
 
@@ -247,11 +204,6 @@ class MappedBy extends ColumnConstraint {
 
   MappedBy(String name, this.mapper) : super(name);
 
-  @override
-  bool _equalToConstraint(MappedBy other) {
-    return other.mapper.dartCode == mapper.dartCode;
-  }
-
   @override
   final Iterable<AstNode> childNodes = const [];
 
@@ -272,11 +224,6 @@ class JsonKey extends ColumnConstraint {
 
   JsonKey(String name, this.jsonNameToken) : super(name);
 
-  @override
-  bool _equalToConstraint(JsonKey other) {
-    return other.jsonKey == jsonKey;
-  }
-
   @override
   void transformChildren<A>(Transformer<A> transformer, A arg) {}
 }

sqlparser/lib/src/ast/schema/table_definition.dart

@@ -35,11 +35,6 @@ class ForeignKeyClause extends AstNode {
         ...columnNames,
         if (deferrable != null) deferrable,
       ];
-
-  @override
-  bool contentEquals(ForeignKeyClause other) {
-    return other.onDelete == onDelete && other.onUpdate == onUpdate;
-  }
 }
 
 enum InitialDeferrableMode {
@@ -69,11 +64,6 @@ class DeferrableClause extends AstNode {
   @override
   Iterable<AstNode> get childNodes => const Iterable.empty();
 
-  @override
-  bool contentEquals(DeferrableClause other) {
-    return other.not == not && other.declaredInitially == declaredInitially;
-  }
-
   @override
   void transformChildren<A>(Transformer<A> transformer, A arg) {}
 }
@@ -89,13 +79,7 @@ abstract class TableConstraint extends AstNode {
     return visitor.visitTableConstraint(this, arg);
   }
 
-  @override
+  bool constraintEquals(covariant TableConstraint other);
-  bool contentEquals(TableConstraint other) {
-    return other.name == name && _constraintEquals(other);
-  }
-
-  @visibleForOverriding
-  bool _constraintEquals(covariant TableConstraint other);
 }
 
 class KeyClause extends TableConstraint {
@@ -112,7 +96,7 @@ class KeyClause extends TableConstraint {
       : super(name);
 
   @override
-  bool _constraintEquals(KeyClause other) {
+  bool constraintEquals(KeyClause other) {
     return other.isPrimaryKey == isPrimaryKey && other.onConflict == onConflict;
   }
 
@@ -131,7 +115,7 @@ class CheckTable extends TableConstraint {
   CheckTable(String name, this.expression) : super(name);
 
   @override
-  bool _constraintEquals(CheckTable other) => true;
+  bool constraintEquals(CheckTable other) => true;
 
   @override
   void transformChildren<A>(Transformer<A> transformer, A arg) {
@@ -151,7 +135,7 @@ class ForeignKeyTableConstraint extends TableConstraint {
       : super(name);
 
   @override
-  bool _constraintEquals(ForeignKeyTableConstraint other) => true;
+  bool constraintEquals(ForeignKeyTableConstraint other) => true;
 
   @override
   void transformChildren<A>(Transformer<A> transformer, A arg) {

sqlparser/lib/src/ast/statements/block.dart

@@ -20,7 +20,4 @@ class Block extends AstNode {
 
   @override
   Iterable<AstNode> get childNodes => statements;
-
-  @override
-  bool contentEquals(Block other) => true;
 }

sqlparser/lib/src/ast/statements/create_index.dart

@@ -38,11 +38,6 @@ class CreateIndexStatement extends Statement
   @override
   Iterable<AstNode> get childNodes =>
       [on, ...columns, if (where != null) where];
-
-  @override
-  bool contentEquals(CreateIndexStatement other) {
-    return other.indexName == indexName;
-  }
 }
 
 /// Note that this class matches the productions listed at https://www.sqlite.org/syntax/indexed-column.html
@@ -70,7 +65,4 @@ class IndexedColumn extends AstNode {
   void transformChildren<A>(Transformer<A> transformer, A arg) {
     expression = transformer.transformChild(expression, this, arg);
   }
-
-  @override
-  bool contentEquals(IndexedColumn other) => other.ordering == ordering;
 }

sqlparser/lib/src/ast/statements/create_table.dart

@@ -51,14 +51,6 @@ class CreateTableStatement extends TableInducingStatement {
 
   @override
   Iterable<AstNode> get childNodes => [...columns, ...tableConstraints];
-
-  @override
-  bool contentEquals(CreateTableStatement other) {
-    return other.ifNotExists == ifNotExists &&
-        other.tableName == tableName &&
-        other.withoutRowId == withoutRowId &&
-        other.overriddenDataClassName == overriddenDataClassName;
-  }
 }
 
 class CreateVirtualTableStatement extends TableInducingStatement {
@@ -94,12 +86,4 @@ class CreateVirtualTableStatement extends TableInducingStatement {
 
   @override
   Iterable<AstNode> get childNodes => const [];
-
-  @override
-  bool contentEquals(CreateVirtualTableStatement other) {
-    return other.ifNotExists == ifNotExists &&
-        other.tableName == tableName &&
-        other.moduleName == moduleName &&
-        const ListEquality().equals(other.argumentContent, argumentContent);
-  }
 }

sqlparser/lib/src/ast/statements/create_trigger.dart

@@ -46,13 +46,6 @@ class CreateTriggerStatement extends Statement implements CreatingStatement {
         if (when != null) when,
         action,
       ];
-
-  @override
-  bool contentEquals(CreateTriggerStatement other) {
-    return other.ifNotExists == ifNotExists &&
-        other.triggerName == triggerName &&
-        other.mode == mode;
-  }
 }
 
 enum TriggerMode { before, after, insteadOf }
@@ -74,9 +67,6 @@ abstract class TriggerTarget extends AstNode {
   /// Whether this target introduces the "old" table reference in the sub-scope
   /// of the create trigger statement.
   bool get introducesOld;
-
-  @override
-  bool contentEquals(TriggerTarget other) => true;
 }
 
 class DeleteTarget extends TriggerTarget {

sqlparser/lib/src/ast/statements/create_view.dart

@@ -32,11 +32,4 @@ class CreateViewStatement extends Statement implements CreatingStatement {
 
   @override
   Iterable<AstNode> get childNodes => [query];
-
-  @override
-  bool contentEquals(CreateViewStatement other) {
-    return other.ifNotExists == ifNotExists &&
-        other.viewName == viewName &&
-        const ListEquality().equals(other.columns, columns);
-  }
 }

sqlparser/lib/src/ast/statements/delete.dart

@@ -30,7 +30,4 @@ class DeleteStatement extends CrudStatement
         from,
         if (where != null) where,
       ];
-
-  @override
-  bool contentEquals(DeleteStatement other) => true;
 }

sqlparser/lib/src/ast/statements/insert.dart

@@ -56,11 +56,6 @@ class InsertStatement extends CrudStatement implements HasPrimarySource {
         source,
         if (upsert != null) upsert
       ];
-
-  @override
-  bool contentEquals(InsertStatement other) {
-    return other.mode == mode && other.source.runtimeType == source.runtimeType;
-  }
 }
 
 abstract class InsertSource extends AstNode {
@@ -94,9 +89,6 @@ class ValuesSource extends InsertSource {
     return visitor.visitValuesSource(this, arg);
   }
 
-  @override
-  bool contentEquals(ValuesSource other) => true;
-
   @override
   void transformChildren<A>(Transformer<A> transformer, A arg) {
     transformer.transformChildren(values, this, arg);
@@ -117,9 +109,6 @@ class SelectInsertSource extends InsertSource {
     return visitor.visitSelectInsertSource(this, arg);
   }
 
-  @override
-  bool contentEquals(SelectInsertSource other) => true;
-
   @override
   void transformChildren<A>(Transformer<A> transformer, A arg) {
     stmt = transformer.transformChild(stmt, this, arg);
@@ -136,9 +125,6 @@ class DefaultValues extends InsertSource {
     return visitor.visitDefaultValues(this, arg);
   }
 
-  @override
-  bool contentEquals(DefaultValues other) => true;
-
   @override
   void transformChildren<A>(Transformer<A> transformer, A arg) {}
 }

sqlparser/lib/src/ast/statements/invalid.dart

@@ -10,9 +10,6 @@ class InvalidStatement extends Statement {
   @override
   Iterable<AstNode> get childNodes => const Iterable.empty();
 
-  @override
-  bool contentEquals(InvalidStatement other) => true;
-
   @override
   void transformChildren<A>(Transformer<A> transformer, A arg) {}
 }

sqlparser/lib/src/ast/statements/select.dart

@@ -72,11 +72,6 @@ class SelectStatement extends BaseSelectStatement
       if (orderBy != null) orderBy,
     ];
   }
-
-  @override
-  bool contentEquals(SelectStatement other) {
-    return other.distinct == distinct;
-  }
 }
 
 class CompoundSelectStatement extends BaseSelectStatement {
@@ -109,12 +104,6 @@ class CompoundSelectStatement extends BaseSelectStatement {
     base = transformer.transformChild(base, this, arg);
     transformer.transformChildren(additional, this, arg);
   }
-
-  @override
-  bool contentEquals(CompoundSelectStatement other) {
-    // this class doesn't contain anything but child nodes
-    return true;
-  }
 }
 
 /// A select statement of the form `VALUES (expr-list), ..., (expr-list-N)`.
@@ -137,9 +126,6 @@ class ValuesSelectStatement extends BaseSelectStatement
 
   @override
   Iterable<AstNode> get childNodes => values;
-
-  @override
-  bool contentEquals(ValuesSelectStatement other) => true;
 }
 
 abstract class ResultColumn extends AstNode {}
@@ -157,11 +143,6 @@ class StarResultColumn extends ResultColumn {
   @override
   void transformChildren<A>(Transformer<A> transformer, A arg) {}
 
-  @override
-  bool contentEquals(StarResultColumn other) {
-    return other.tableName == tableName;
-  }
-
   @override
   R accept<A, R>(AstVisitor<A, R> visitor, A arg) {
     return visitor.visitStarResultColumn(this, arg);
@@ -191,11 +172,6 @@ class ExpressionResultColumn extends ResultColumn
   R accept<A, R>(AstVisitor<A, R> visitor, A arg) {
     return visitor.visitExpressionResultColumn(this, arg);
   }
-
-  @override
-  bool contentEquals(ExpressionResultColumn other) {
-    return other.as == as;
-  }
 }
 
 class GroupBy extends AstNode {
@@ -218,11 +194,6 @@ class GroupBy extends AstNode {
 
   @override
   Iterable<AstNode> get childNodes => [...by, if (having != null) having];
-
-  @override
-  bool contentEquals(GroupBy other) {
-    return true; // Defined via child nodes
-  }
 }
 
 enum CompoundSelectMode {
@@ -256,7 +227,4 @@ class CompoundSelectPart extends AstNode {
   void transformChildren<A>(Transformer<A> transformer, A arg) {
     select = transformer.transformChild(select, this, arg);
   }
-
-  @override
-  bool contentEquals(CompoundSelectPart other) => mode == other.mode;
 }

sqlparser/lib/src/ast/statements/update.dart

@@ -54,11 +54,6 @@ class UpdateStatement extends CrudStatement
         if (where != null) where,
       ];
 
-  @override
-  bool contentEquals(UpdateStatement other) {
-    return other.or == or;
-  }
-
   static FailureMode failureModeFromToken(TokenType token) {
     return _tokensToMode[token];
   }
@@ -83,7 +78,4 @@ class SetComponent extends AstNode {
 
   @override
   Iterable<AstNode> get childNodes => [column, expression];
-
-  @override
-  bool contentEquals(SetComponent other) => true;
 }

sqlparser/lib/src/utils/ast_equality.dart

@@ -1,16 +1,693 @@
+import 'package:collection/collection.dart';
 import 'package:sqlparser/src/ast/ast.dart';
 
+/// Visitor enforcing the equality of two ast nodes.
+class EqualityEnforcingVisitor implements AstVisitor<void, void> {
+  // The current ast node. Visitor methods will compare the node they receive to
+  // this one.
+  AstNode _current;
+  // Whether to check for deep equality too.
+  final bool _considerChildren;
+
+  /// Creates a visitor enforcing equality to the given node.
+  ///
+  /// The [visit] methods of this visitor will throw an [NotEqualException]
+  /// if they receive a node that is different to the node passed here.
+  ///
+  /// When [considerChildren] is true (the default), it also considers child
+  /// nodes, thus enforcing deep equality.
+  EqualityEnforcingVisitor(this._current, {bool considerChildren = true})
+      : _considerChildren = considerChildren;
+
+  void _check(AstNode childOfCurrent, AstNode childOfOther) {
+    if (identical(childOfCurrent, childOfOther)) return;
+
+    if ((childOfCurrent == null) != (childOfOther == null)) {
+      throw NotEqualException('$childOfCurrent and $childOfOther');
+    }
+
+    // Both non nullable here
+    final savedCurrent = _current;
+    _current = childOfCurrent;
+    visit(childOfOther, null);
+    _current = savedCurrent;
+  }
+
+  void _checkChildren(AstNode other) {
+    if (!_considerChildren) return;
+
+    final currentChildren = _current.childNodes.iterator;
+    final otherChildren = other.childNodes.iterator;
+
+    // always move both iterators
+    while (currentChildren.moveNext() & otherChildren.moveNext()) {
+      _check(currentChildren.current, otherChildren.current);
+    }
+
+    if (currentChildren.moveNext() || otherChildren.moveNext()) {
+      throw NotEqualException(
+          "$_current and $other don't have an equal amount of children");
+    }
+  }
+
+  Null /*Never*/ _notEqual(AstNode other) {
+    throw NotEqualException('$_current and $other');
+  }
+
+  T _currentAs<T extends AstNode>(T context) {
+    final current = _current;
+    if (current is T) return current;
+
+    _notEqual(context);
+    return null;
+  }
+
+  void _assert(bool contentEqual, AstNode context) {
+    if (!contentEqual) _notEqual(context);
+  }
+
+  @override
+  void visitAggregateExpression(AggregateExpression e, void arg) {
+    final current = _currentAs<AggregateExpression>(e);
+    _assert(current.name == e.name && current.windowName == e.windowName, e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitBetweenExpression(BetweenExpression e, void arg) {
+    final current = _currentAs<BetweenExpression>(e);
+    _assert(current.not == e.not, e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitBinaryExpression(BinaryExpression e, void arg) {
+    final current = _currentAs<BinaryExpression>(e);
+    _assert(current.operator.type == e.operator.type, e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitBlock(Block block, void arg) {
+    _currentAs<Block>(block);
+    _checkChildren(block);
+  }
+
+  @override
+  void visitBooleanLiteral(BooleanLiteral e, void arg) {
+    final current = _currentAs<BooleanLiteral>(e);
+    _assert(current.value == e.value, e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitCaseExpression(CaseExpression e, void arg) {
+    _currentAs<CaseExpression>(e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitCastExpression(CastExpression e, void arg) {
+    final current = _currentAs<CastExpression>(e);
+    _assert(current.typeName == e.typeName, e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitCollateExpression(CollateExpression e, void arg) {
+    final current = _currentAs<CollateExpression>(e);
+    _assert(current.collateFunction.type == e.collateFunction.type, e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitColumnConstraint(ColumnConstraint e, void arg) {
+    final current = _currentAs<ColumnConstraint>(e);
+    _assert(current.name == e.name, e);
+
+    if (e is NotNull) {
+      _assert(current is NotNull && current.onConflict == e.onConflict, e);
+    } else if (e is PrimaryKeyColumn) {
+      _assert(
+          current is PrimaryKeyColumn &&
+              current.autoIncrement == e.autoIncrement &&
+              current.mode == e.mode &&
+              current.onConflict == e.onConflict,
+          e);
+    } else if (e is UniqueColumn) {
+      _assert(current is UniqueColumn && current.onConflict == e.onConflict, e);
+    } else if (e is CheckColumn) {
+      _assert(current is CheckColumn, e);
+    } else if (e is MappedBy) {
+      _assert(
+          current is MappedBy && current.mapper.dartCode == e.mapper.dartCode,
+          e);
+    } else if (e is JsonKey) {
+      _assert(current is JsonKey && current.jsonKey == e.jsonKey, e);
+    } else {
+      _assert(current.runtimeType == e.runtimeType, e);
+    }
+
+    _checkChildren(e);
+  }
+
+  @override
+  void visitColumnDefinition(ColumnDefinition e, void arg) {
+    final current = _currentAs<ColumnDefinition>(e);
+    _assert(
+        current.columnName == e.columnName && current.typeName == e.typeName,
+        e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitCommonTableExpression(CommonTableExpression e, void arg) {
+    final current = _currentAs<CommonTableExpression>(e);
+    _assert(current.cteTableName == e.cteTableName, e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitCompoundSelectPart(CompoundSelectPart e, void arg) {
+    final current = _currentAs<CompoundSelectPart>(e);
+    _assert(current.mode == e.mode, e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitCompoundSelectStatement(CompoundSelectStatement e, void arg) {
+    _currentAs<CompoundSelectStatement>(e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitCreateIndexStatement(CreateIndexStatement e, void arg) {
+    final current = _currentAs<CreateIndexStatement>(e);
+    _assert(
+        current.indexName == e.indexName &&
+            current.unique == e.unique &&
+            current.ifNotExists == e.ifNotExists,
+        e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitCreateTableStatement(CreateTableStatement e, void arg) {
+    final current = _currentAs<CreateTableStatement>(e);
+    _assert(
+        current.ifNotExists == e.ifNotExists &&
+            current.tableName == e.tableName &&
+            current.withoutRowId == e.withoutRowId &&
+            current.overriddenDataClassName == e.overriddenDataClassName,
+        e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitCreateTriggerStatement(CreateTriggerStatement e, void arg) {
+    final current = _currentAs<CreateTriggerStatement>(e);
+    _assert(
+        current.ifNotExists == e.ifNotExists &&
+            current.triggerName == e.triggerName &&
+            current.mode == e.mode,
+        e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitCreateViewStatement(CreateViewStatement e, void arg) {
+    final current = _currentAs<CreateViewStatement>(e);
+    _assert(
+        current.ifNotExists == e.ifNotExists &&
+            current.viewName == e.viewName &&
+            const ListEquality().equals(current.columns, e.columns),
+        e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitCreateVirtualTableStatement(
+      CreateVirtualTableStatement e, void arg) {
+    final current = _currentAs<CreateVirtualTableStatement>(e);
+    _assert(
+        current.ifNotExists == e.ifNotExists &&
+            current.tableName == e.tableName &&
+            current.moduleName == e.moduleName &&
+            const ListEquality()
+                .equals(current.argumentContent, e.argumentContent),
+        e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitDartPlaceholder(DartPlaceholder e, void arg) {
+    final current = _currentAs<DartPlaceholder>(e);
+    _assert(current.name == e.name && current.runtimeType == e.runtimeType, e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitDefaultValues(DefaultValues e, void arg) {
+    _currentAs<DefaultValues>(e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitDeferrableClause(DeferrableClause e, void arg) {
+    final current = _currentAs<DeferrableClause>(e);
+    _assert(
+        current.not == e.not &&
+            current.declaredInitially == e.declaredInitially,
+        e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitDeleteStatement(DeleteStatement e, void arg) {
+    _currentAs<DeleteStatement>(e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitDeleteTriggerTarget(DeleteTarget e, void arg) {
+    _currentAs<DeleteTarget>(e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitDoNothing(DoNothing e, void arg) {
+    _currentAs<DoNothing>(e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitDoUpdate(DoUpdate e, void arg) {
+    _currentAs<DoUpdate>(e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitExists(ExistsExpression e, void arg) {
+    _currentAs<ExistsExpression>(e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitExpressionFunctionParameters(ExprFunctionParameters e, void arg) {
+    final current = _currentAs<ExprFunctionParameters>(e);
+    _assert(current.distinct == e.distinct, e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitExpressionResultColumn(ExpressionResultColumn e, void arg) {
+    final current = _currentAs<ExpressionResultColumn>(e);
+    _assert(current.as == e.as, e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitForeignKeyClause(ForeignKeyClause e, void arg) {
+    final current = _currentAs<ForeignKeyClause>(e);
+    _assert(
+        current.onDelete == e.onDelete && current.onUpdate == e.onUpdate, e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitFrameSpec(FrameSpec e, void arg) {
+    final current = _currentAs<FrameSpec>(e);
+    _assert(
+        current.type == e.type &&
+            current.excludeMode == e.excludeMode &&
+            current.start == e.start &&
+            e.end == e.end,
+        e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitFunction(FunctionExpression e, void arg) {
+    final current = _currentAs<FunctionExpression>(e);
+    _assert(current.name == e.name, e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitGroupBy(GroupBy e, void arg) {
+    _currentAs<GroupBy>(e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitInExpression(InExpression e, void arg) {
+    final current = _currentAs<InExpression>(e);
+    _assert(current.not == e.not, e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitIndexedColumn(IndexedColumn e, void arg) {
+    final current = _currentAs<IndexedColumn>(e);
+    _assert(current.ordering == e.ordering, e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitInsertStatement(InsertStatement e, void arg) {
+    final current = _currentAs<InsertStatement>(e);
+    _assert(current.mode == e.mode, e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitInsertTriggerTarget(InsertTarget e, void arg) {
+    _currentAs<InsertTarget>(e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitInvalidStatement(InvalidStatement e, void arg) {
+    _currentAs<InvalidStatement>(e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitIsExpression(IsExpression e, void arg) {
+    final current = _currentAs<IsExpression>(e);
+    _assert(current.negated == e.negated, e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitIsNullExpression(IsNullExpression e, void arg) {
+    final current = _currentAs<IsNullExpression>(e);
+    _assert(current.negated == e.negated, e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitJoin(Join e, void arg) {
+    final current = _currentAs<Join>(e);
+
+    if (current.natural != e.natural || current.operator != e.operator) {
+      _notEqual(e);
+    }
+
+    final constraint = current.constraint;
+    if (constraint is OnConstraint) {
+      _assert(e.constraint is OnConstraint, e);
+    } else if (constraint is UsingConstraint) {
+      if (e.constraint is! UsingConstraint) {
+        _notEqual(e);
+      }
+      final typedOther = e.constraint as UsingConstraint;
+
+      _assert(
+          const ListEquality()
+              .equals(constraint.columnNames, typedOther.columnNames),
+          e);
+    }
+
+    _checkChildren(e);
+  }
+
+  @override
+  void visitJoinClause(JoinClause e, void arg) {
+    _currentAs<JoinClause>(e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitLimit(Limit e, void arg) {
+    _currentAs<Limit>(e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitMoorDeclaredStatement(DeclaredStatement e, void arg) {
+    final current = _currentAs<DeclaredStatement>(e);
+    _assert(current.identifier == e.identifier && current.as == e.as, e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitMoorFile(MoorFile e, void arg) {
+    _currentAs<MoorFile>(e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitMoorImportStatement(ImportStatement e, void arg) {
+    final current = _currentAs<ImportStatement>(e);
+    _assert(current.importedFile == e.importedFile, e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitMoorNestedStarResultColumn(NestedStarResultColumn e, void arg) {
+    final current = _currentAs<NestedStarResultColumn>(e);
+    _assert(current.tableName == e.tableName, e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitMoorStatementParameter(StatementParameter e, void arg) {
+    if (e is VariableTypeHint) {
+      final current = _currentAs<VariableTypeHint>(e);
+      _assert(current.typeName == e.typeName, e);
+    } else if (e is DartPlaceholderDefaultValue) {
+      final current = _currentAs<DartPlaceholderDefaultValue>(e);
+      _assert(current.variableName == e.variableName, e);
+    }
+
+    _checkChildren(e);
+  }
+
+  @override
+  void visitNamedVariable(ColonNamedVariable e, void arg) {
+    final current = _currentAs<ColonNamedVariable>(e);
+    _assert(current.name == e.name, e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitNullLiteral(NullLiteral e, void arg) {
+    _currentAs<NullLiteral>(e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitNumberedVariable(NumberedVariable e, void arg) {
+    final current = _currentAs<NumberedVariable>(e);
+    _assert(current.explicitIndex == e.explicitIndex, e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitNumericLiteral(NumericLiteral e, void arg) {
+    final current = _currentAs<NumericLiteral>(e);
+    _assert(current.value == e.value, e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitOrderBy(OrderBy e, void arg) {
+    _currentAs<OrderBy>(e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitOrderingTerm(OrderingTerm e, void arg) {
+    final current = _currentAs<OrderingTerm>(e);
+    _assert(
+        current.orderingMode == e.orderingMode && current.nulls == e.nulls, e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitParentheses(Parentheses e, void arg) {
+    _currentAs<Parentheses>(e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitReference(Reference e, void arg) {
+    final current = _currentAs<Reference>(e);
+    _assert(
+        current.tableName == e.tableName && current.columnName == e.columnName,
+        e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitSelectInsertSource(SelectInsertSource e, void arg) {
+    _currentAs<SelectInsertSource>(e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitSelectStatement(SelectStatement e, void arg) {
+    final current = _currentAs<SelectStatement>(e);
+    _assert(current.distinct == e.distinct, e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitSelectStatementAsSource(SelectStatementAsSource e, void arg) {
+    final current = _currentAs<SelectStatementAsSource>(e);
+    _assert(current.as == e.as, e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitSetComponent(SetComponent e, void arg) {
+    _currentAs<SetComponent>(e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitStarFunctionParameter(StarFunctionParameter e, void arg) {
+    _currentAs<StarFunctionParameter>(e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitStarResultColumn(StarResultColumn e, void arg) {
+    final current = _currentAs<StarResultColumn>(e);
+    _assert(current.tableName == e.tableName, e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitStringComparison(StringComparisonExpression e, void arg) {
+    final current = _currentAs<StringComparisonExpression>(e);
+    _assert(current.not == e.not, e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitStringLiteral(StringLiteral e, void arg) {
+    final current = _currentAs<StringLiteral>(e);
+    _assert(current.value == e.value, e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitSubQuery(SubQuery e, void arg) {
+    _currentAs<SubQuery>(e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitTableConstraint(TableConstraint e, void arg) {
+    final current = _currentAs<TableConstraint>(e);
+    _assert(current.name == e.name && e.constraintEquals(current), e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitTableReference(TableReference e, void arg) {
+    final current = _currentAs<TableReference>(e);
+    _assert(current.tableName == e.tableName && current.as == e.as, e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitTableValuedFunction(TableValuedFunction e, void arg) {
+    final current = _currentAs<TableValuedFunction>(e);
+    _assert(current.name == e.name, e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitTimeConstantLiteral(TimeConstantLiteral e, void arg) {
+    final current = _currentAs<TimeConstantLiteral>(e);
+    _assert(current.kind == e.kind, e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitTuple(Tuple e, void arg) {
+    _currentAs<Tuple>(e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitUnaryExpression(UnaryExpression e, void arg) {
+    final current = _currentAs<UnaryExpression>(e);
+    _assert(current.operator.type == e.operator.type, e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitUpdateStatement(UpdateStatement e, void arg) {
+    final current = _currentAs<UpdateStatement>(e);
+    _assert(current.or == e.or, e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitUpdateTriggerTarget(UpdateTarget e, void arg) {
+    _currentAs<UpdateTarget>(e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitUpsertClause(UpsertClause e, void arg) {
+    _currentAs<UpsertClause>(e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitValuesSelectStatement(ValuesSelectStatement e, void arg) {
+    _currentAs<ValuesSelectStatement>(e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitValuesSource(ValuesSource e, void arg) {
+    _currentAs<ValuesSource>(e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitWhen(WhenComponent e, void arg) {
+    _currentAs<WhenComponent>(e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitWindowDefinition(WindowDefinition e, void arg) {
+    final current = _currentAs<WindowDefinition>(e);
+    _assert(current.baseWindowName == e.baseWindowName, e);
+    _checkChildren(e);
+  }
+
+  @override
+  void visitWithClause(WithClause e, void arg) {
+    final current = _currentAs<WithClause>(e);
+    _assert(current.recursive == e.recursive, e);
+    _checkChildren(e);
+  }
+}
+
 /// Checks whether [a] and [b] are equal. If they aren't, throws an exception.
 void enforceEqual(AstNode a, AstNode b) {
-  if (a.runtimeType != b.runtimeType) {
+  EqualityEnforcingVisitor(a).visit(b, null);
-    throw ArgumentError('Not equal: First was $a, second $b');
+}
-  }
 
-  if (!a.contentEquals(b)) {
+/// Thrown by the [EqualityEnforcingVisitor] when two nodes were determined to
-    throw ArgumentError('Content not equal: $a and $b');
+/// be non-equal.
-  }
+class NotEqualException implements Exception {
+  final String message;
 
-  return enforceEqualIterable(a.childNodes, b.childNodes);
+  NotEqualException(this.message);
+
+  @override
+  String toString() {
+    return 'Not equal: $message';
+  }
 }
 
 void enforceEqualIterable(Iterable<AstNode> a, Iterable<AstNode> b) {